eagletangogreen, i read someone on m3forum.net that using brake from another car with custom braket is not good safety/performance wise. What is your take on that? I saw ton of cheap bbk for sale on ebay from amg, porsche and they look very good. It would be awesome if we can have someone do a custom bracket and fit those brake on the m car.

IMO, 6-7k for a brembo bbk is outrageous.

Dont quote me on this but I am pretty sure that the same St-60 witch is the 6piston calipers from the Z is the same as on the M just the brackets are diffrent to mount them on the particular car.. So if this is true you could buy some and just order the bracket from stoptech to mount on your M.. However you will need new rotors since the Z has a 5x114 pattern ands will not fit on a 5x120... In the end the price for a set of stoptech are way cheaper than the brembos, and are more user friendly.. The 6 piston are waayy over kill for street use, the only reason i went with 6 is because there seems to be more choices for brake pad compound. I have had both the four and the six pistons and you cant tell the difference, (braking will come down to what your tires can handle) if you were racing for cash i would go with the 6 pistons since they stay a bit cooler under heavy load, and the 6 look a bit more sexy..
Another thing with Stoptech is if you ever have a problem they are in the US and can get parts and a full rebuild if needed in less than a week..

But yeah your right frankenstiening some brakes to make them fit on your car is not a brite idea..